Bibliocad

Bibliocad, created in 1999, is a library where you can download CAD 2D and 3D drawings and resources to be applied in architecture, engineering, design and the building industry. This library contains “collective knowledge” generated by the contribution of colleagues who send their works to share them with the global community.

Bibliocad has more than 30000 dwg, max and 3D files, among others, grouped into 36 categories.
Bibliocad is a free zone of collaboration between design and building experts and architects. Here you can find drawings for general use, building details, design tools, landscape elements and other resources for professional use. All these resources are in CAD file format or are AutoCAD® compatible.

http://www.autodesk.com/products/autocad/overview